The first game in the Super Mario Bros. series, but the fourth game overall that stars Mario, and the game that singlehandedly kicked off the Eight Bit Era. After appearing in Donkey Kong, Mario Bros., and Wrecking Crew, the Mario brothers moved on to the game that set loads of standards. Not just for platform games, but just about any genre that used conventions established in this game.The general story is that Bowser, the ornery King of the Koopas, has conquered the Mushroom Kingdom and turned all of her subjects into background textures— er, bricks and shrubbery. The Kingdom's Princess is the only one who can revert his dark magic, but he has kidnapped her in order to prevent this. Mario, ever the gallant one, storms each of Bowser's castles looking for her. Unfortunately for Mario (and you), Bowser has several body doubles, and there's no way to tell who's the real one, so it's long road ahead.Really, the importance of this game can be easy to underestimate by today's standards. There simply weren't games like it. "Golden Age" games were more simple, and had fallen out of favor in the US due to the The Great Video Game Crash of 1983, and games on PCs were more complex, which meant they didn't have the accessibility or mass appeal.This game hit that sweet spot in the middle. It was simple enough that it could attain mass appeal, yet it also exhibited enough depth to be stimulating for more devoted gamers. Some might dismiss its sales due to being bundled, but it was sold separately in Japannote and in North America at first, and was still a smash hit. This game helped sell the NES to a game-weary audience, and elevated Nintendo to the top of the gaming companies.And this of course had loads of sequels and follow-ups in the Super Mario Bros. series, as well as loads of imitators.The original game was remade with SNES graphics along with the other NES titles in Super Mario All-Stars. There was also a Game Boy Color version called Super Mario Bros. Deluxe. This included a challenge mode where you had to get a high score, collect 5 red coins, and find the Yoshi egg in each stage; a two-player race mode; badges and other images awarded for achievements; a high-score table; extra utilities and printables; a hidden "You vs. Boo" mode (a one-player version of the two-player game); and a hidden conversion of Super Mario Bros.: The Lost Levels.Nobuo Uematsu has stated that the theme music, originally created by Koji Kondo, should be Japan's national anthem.
This game provides examples of:
Actually a Doombot: The first seven "Bowsers" are actually enemies somehow in disguise as him. Flinging fireballs at the fake Bowsers will reveal their true forms.
All There in the Manual: The Koopa are a clan of sorcerers who have brought the Mushroom Kingdom to ruin by transforming its citizens into the bricks you break (and thus the items are "gifts" from the transformed citizens to help you) and various other background objects. The only one who can break this curse is Princess Pea..., er "Toadstool"note She was always called "Peach" in Japan; the eventual compromise was making her full legal name "Princess Peach Toadstool", which is why Bowser has kidnapped her. This bit of lore was dropped in later games.
Antepiece: the game has great level design involving interesting yet accessible setpieces. One tool it'll use is to build up to a complicated setpiece with an "antepiece". For example, in the first level, there's a part with a staircase followed by a pit; jumping up the staircase without falling into the pit, and then getting over the pit, is a rather hard and scary proposition. So there's a part right before it which is mostly the same, except the pit won't kill you. This allows you to practice the setpiece in a safe environment. You can read more and see a picture of this setpiece-antepiece pair here: 
Art Evolution: According to this Iwata Asks, Miyamoto utilised external illustrators to flesh out his rough pencil sketches since Donkey Kong. When it came time to do this game's (Japanese) package illustrationnote which was eventually used in the U.S. for the "How to Win at Super Mario Bros." strategy guide, Miyamoto had to do the art himself, since there was no time left for him to hire a mainstream artist. This was the result.◊ It was Yoichi Kotabe who fleshed out the designs of the characters since then. Notable mention goes to Bowser. Miyamoto himself was aiming for the appearance of an ox for Bowser's design, even though he's supposed to be a turtle. Upon reflection on this, Miyamoto remarked, "I'd been drawing something completely incomprehensible - a turtle's body with an ox's head!" In a Mythology Gag, Midbus, Bowser's rival from Mario & Luigi: Bowser's Inside Story, more closely resembles an ox, with some boar characteristics thrown in.
Artifact Title: Although Super Mario Bros. has more elaborate play mechanics and greater production values than the original Mario Bros., it lacked its predecessor's 2-Player co-op mode (which was that game's big selling point). Since the 2-Player mode in this game is that of the alternating type, it reduces Luigi's role to a mere afterthought (since there's no point of having a separate Player 2 character if the players have to take turns anyway). The Japanese sequel would try to justify Luigi's inclusion by removing the 2-Player mode and turning Luigi into an alternate character with different characteristics, while the 2-Player mode in Super Mario Bros. 3 is designed around the fact that both players can split the stages among themselves or even compete against each other in a Mario Bros.-style minigame.
The Artifact: Mario and Luigi being plumbers and travelling through pipes. This made sense in Mario Bros., which was set in New York's sewers; not so much in the Mushroom Kingdom. However, it became an integral part of the gameplay and setting, and its incongruous nature helped create the series' World of Chaos reputation.
Ascended Glitch: The multi-coin blocks were reportedly a programming error that was left in because they liked it.
Attract Mode: It features one, and the computer's one of the worst Mario players ever.
Bald of Evil: Bowser. Averted in both the original artwork and the Super Mario All-Stars remake.
Battle Theme Music: Averted in the original version, played straight in the All-Stars version.
Cheated Angle: In the original game, the Mario Bros. always have their head to the side they're walking towards, even when they aren't moving and the rest of their body is facing the screen. The only time they ever fully face the viewer is if they're dying.
Color-Coded for Your Convenience: Red mushrooms (extra hit point) vs. green (1-Up), red Koopas (they patrol specific areas) vs. green (they come straight at you). Oddly subverted in the Goombas, whose color-coding only matches the level.
The backstory, All There in the Manual, explains how the Koopa clan transformed the citizens of the Mushroom Kingdom, and only the princess can undo this. The later games never mention this.
The game also used Ratchet Scrolling, which prevented players from going back. Most Mario games after this abandoned this type of scrolling for Auto-Scrolling Level in a few places while allowing backtracking in everything else.
The timer also ticked away at a much faster pace compared to the later Mario games.
Game Mod: An official one, "All Night Nippon Super Mario Bros.". Here, all the enemy sprites were changed into Japanese celebrities. It was given out as a raffle prize on the Japanese TV show "All Night Nippon".
Gameplay and Story Segregation: There is actually only one Buzzy Beetle that can be killed with fireballs in this game. It's disguised as Bowser at the end of World 3-4.
Guide Dang It: Each x-1 level has a hidden 1-Up Mushroom in it. Besides the one in 1-1, they only appear if you've gotten all the coins in the previous x-3 level or used a Warp Pipe (e.g. to get the one in 2-1, you need to get all the coins in 1-3).
Infinite 1-Ups: Line a Koopa shell just right against a staircase at the end of 3-1, and your jumps will turn into a chain reaction, triggering loads of points followed by One Ups.
Game-Breaking Bug: But woe to you if you exceed 127 lives, because the life counter will overflow into negative lives, causing your next death to be a Game Over.Details The game stores your remaining lives in an 8-bit signed integer (which has a range from -128 to 127), hence the overflow.
In Name Only: Aside from the presence of Mario, Luigi, turtle enemies, and coins, Super Mario Bros really doesn't have anything to do with Mario Bros., although it does have some similar elements (you can still attack enemies from below when they are on brick platforms).
The overworld theme has become the iconic theme of the Mario series, as well as nearly every crossover and non video game appearance Mario has had.
Subverted in the All-Stars version though, which uses an arrangement of the underwater level theme as the title theme.
Marathon Level: Level 8-1 is looooooooooooong. Even harder than making all of the tricky jumps is reaching the end before time runs out!
Market-Based Title: Subverted. Copyrights documents (and at least one brochure for the arcade version) suggest that Nintendo originally considered renaming the game Mario's Adventure for the American market, but they decided to keep the original name instead.
Minus World: A famous example, coined by Nintendo Power's coverage of the glitch. Japan, meanwhile, discovered even more such worlds through a process that involves swapping out the game's cartridge with Tennis while the console's still running.
Nintendo Hard: Although at the lower end compared to other infamously hard games.
1-Up: Trope Maker. The green 1-Up Mushrooms have appeared in almost every other Mario game since.
Pac-Man Fever: Lots of sound effects from this game have turned up in children's TV shows, particularly in scenes set at arcades (there were arcade cabinet versions of the game, but it's unlikely any of those writers knew that).
Palette Swap: Not just with enemies; the bushes and clouds use the same tiles.
Backgrounds, too; Worlds 3 and 6 apparently take place at night.
Required by the way levels were stored. Each "object" in the level had a "page select" flag which, when set, told the game to advance one screenful to the right. There was no code for going back one screen, however, and as there could be a variable number of objects per page, the algorithms involved would have been a bit too complicated for the NES, where every byte and every clock cycle counted (and they were already running low on ROM space as it was). So while the game could be told to go to the next screen, there was no way to start loading objects from the previous screen, hence why you can only go right.
The Game Boy Color version does allow you to scroll back slightly, but only because the screen is smaller than the NES version's.
Slippy-Slidey Ice World: Worlds 3 and 5, although "snow" in this game is just recolored trees and pipes. The All-Stars version of the game improves on this by making the ground actually look snowy.
Super Drowning Skills/Super Not Drowning Skills: Yes, both of them. If you're underwater, nothing aside from the standard timer can stop you from staying under for as long as you want. On the other hand, falling into a pit filled with water doesn't even slow your fall.
This Was His True Form: If defeated with fireballs rather than being thrown into the lava, the Bowsers of Worlds 1-7 are revealed to be simple minor enemies which have taken Bowser's form, likely using more of that Koopa Clan magic you only ever hear about in the manual.
Timed Mission: Every single level. The timer also counts down faster here than in Mario's later games.